Circuit Description
The brake switch informs the electronic brake control module (EBCM) when the brake is depressed. The brake switch is normally closed, supplying 12 volts to the EBCM when the brake is released. When the brake pedal is pressed, voltage on the TCC brake switch signal circuit is 0 volts.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0161 Antilock Brake System (ABS) / Traction Control System (TCS) Brake Switch
Conditions for Running the DTC
Any of the following conditions may cause the DTC to run.
| • | The vehicle accelerates from 0 km/h (0 mph) to a speed greater than 56 km/h (35 mph). |
| • | The vehicle experiences an ABS event involving all hydraulic circuits. |
| • | The EBCM detects that the master cylinder pressure is greater than 1400 kPa (200 PSI) and that the vehicle is decelerating. |
Conditions for Setting the DTC
Any of the following conditions may cause the DTC to set.
| • | Voltage on the TCC brake switch signal circuit is always low. |
| • | Voltage on the TCC brake switch signal circuit is always high. |
| • | Voltage on the TCC brake switch signal circuit is high for 0.5-4.0 seconds when voltage is expected to be low. |
Action Taken When the DTC Sets
| • | The EBCM disables the VSES. |
| • | The TCS operates with engine torque reduction capability only. |
| • | The message center displays the service stability system message. |
Conditions for Clearing the DTC
The Conditions for Setting the DTC are no longer present and you use the scan tool Clear DTCs function.
Diagnostic Aids
Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to Testing for Intermittent Conditions and Poor Connections , Connector Repairs , Testing for Electrical Intermittents and to Wiring Repairs in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views and Lighting Systems Connector End Views in Lighting Systems | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the scan tool display Off? | Go to Step 3 | Go to Step 5 |
3 |
Does the scan tool display On? | Go to Diagnostic Aids | Go to Step 4 |
Does the scan tool display On? | Go to Step 9 | Go to Step 7 | |
Does the scan tool display Off? | Go to Step 9 | Go to Step 6 | |
6 | Test the ignition 3 voltage circuit and the TCC brake switch signal circuit for an open or a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 8 |
7 | Test the TCC brake switch signal circuit for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 8 |
8 | Inspect for poor connections at the harness connector of the electronic brake control module (EBCM). Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 10 |
9 | Inspect for poor connections at the harness connector of the stop lamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 11 |
10 | Replace the EBCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 12 | -- |
11 | Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement in Lighting Systems. Did you complete the replacement? | Go to Step 12 | -- |
12 |
Does the DTC reset? | Go to Step 2 | System OK |
